In recent years, with the spread of personal computers and the rise of networks, e-mail for transmitting and receiving text data via such networks has become more common. With e-mail, it is possible to attach files of various types to the text-data body of the mail, so an Internet facsimile for transmitting and receiving image data via e-mail to which image TIFF (Tag Image File Format) files are attached has been proposed.
Similarly, with the RFC 2532 (Expanded Facsimile Using Internet Mail) issued by the IETF (Internet Engineering Task Force), an internet facsimile full mode has been proposed that notifies a sending device by e-mail that a receiving device has properly received an e-mail sent by the sending device when the receiving device has properly received an e-mail with an image TIFF file attachment transmitted by the sending device.
With this type of Internet facsimile, ordinarily, during the time it takes the image data transmitted from the sending device to reach the receiving device, the e-mail passes through a plurality of mail servers. As a result, delay in transmission can be a factor. Also, certain mail servers limit the size of the attached file in order to reduce the processing load at the server, and when such a mail server exists in the transmission route there is always a chance that a large file attachment might not be transmitted properly.
By contrast, in the case of a mail address existing in the same local environment, such as on the same network, there is no need for the e-mail to pass through a server, thus eliminating server-generated delays and errors in transmission.
Consequently, a communications device equipped with the capability to determine quickly and easily whether or not a given e-mail with attached image file is to be routed through a mail server depending on the address would be able to reduce the processing load on the mail server.